1. Field of the Invention
The present invention relates to valves for use in fluid systems, and to methods for controlling fluid flow. More particularly, the present invention relates to improvements which may be easily installed into fluid systems, such as heating systems, in order to provide for automated precision-controlled operation of system components that are presently operated manually.
2. Description of the Related Art
Many types of heating systems may be used to provide heat to spaces within homes and buildings, and can typically include a heat exchanger, distribution piping, valves and radiators. Closed-loop heating systems operate by circulating a fluid from a heat exchanger, such as a boiler, through piping to one or more radiators that may be located in one or more spaces. Hydronic heating systems typically use water as the heat transfer medium and may also include recirculation pumps, while steam heating systems use steam as the heat transfer medium and do not require such pumps.
Throughout the Twentieth Century, closed-loop heating systems were regularly constructed in homes and buildings, particularly in older cities in the eastern United States. Such systems often include manual operating valves for controlling the flow of fluid into radiators, and, therefore, the radiation of heat into the space. While manual operating valves enable occupants to customize fluid flow to an individual space, such valves are unable to automatically respond to changes in the environment inside or outside the space, including the opening or closing of windows; varying environmental conditions such as solar gains or wind exposure; internal activities such as cooking, appliance use or increased occupancy; or the individual habits, ages, preferences or health concerns of occupants of the space. Moreover, enabling occupants to modify fluid flow to one particular space can have ramifications on the fluid flow and heat loading in surrounding spaces, and may create an imbalance in heat loading across the entire system.
Thermostatic radiator valves (“TRV”) were first conceived in the mid-1940s as a way to automate the control of fluid flow to a radiator and, therefore, to automate the control of the temperature in the space in which the radiator is located. TRVs are self-acting capillary actuated devices that modulate the flow of fluid in response to variations in room temperatures or according to preset instructions, and typically include a valve, a sensor or other automatic controller, and an actuator. The sensor senses the temperature in a space and is connected to the actuator, which is adapted to control the operation of the TRV. When the temperature sensed in a space falls below or rises above a set point, the sensor will direct the actuator to open or close the TRV, as necessary, in order to increase or decrease fluid flow to a radiator. The actuator may also be directed to operate the TRV based on a preset schedule or according to other instructions. TRVs are typically used in hydronic and steam systems, and can increase the efficiency of such systems by reducing heating losses and by rapidly responding to changes in temperature, but generally do not require any manual action on the part of an operator.
Because a TRV can provide many advantages in terms of ease of operation and improved system efficiency, it is desirable to replace manually operated valves in older closed-loop systems with TRVs. However, retrofitting fluid systems that are installed in older structures, particularly heating systems that may have been built according to obsolete standards or in unique configurations, can prove to be a major challenge. Piping arrangements, system materials and other variations may have a significant impact on the costs and the difficulties associated with upgrading an existing manually operable system to automatic control.
Accordingly, there exists a need for an easy-to-install TRV insert which may be quickly and inexpensively retrofitted into existing fluid systems, and a simple method for installing TRV inserts into such systems, in order to convert such systems from manual to automatic control.